In 1976 and 1977 a total of 457 male corn refinery workers participated in a cross-sectional study to ascertain the respiratory effects of sulfur dioxide at low levels in the work environment. The concentrations of mass respirable particulates and water-soluble sulfates were shown to be very low. Health effects were assessed by a respiratory questionnaire and by lung spirometry. Preliminary analysis of the data indicated that prevalence rates for cough, phlegm, wheezing, and a history of chest illness all increased with increasing concentrations of sulfur dioxide. Lung functions tests (FEV1, FVC) were analyzed by initially standardizing for age and height, and then the effects of smoking and sulfur dioxide were examined by multiple regression techniques. This analysis suggested that neither smoking nor sulfur dioxide exposure was detrimental to lung function in these workers. Further analyses of the exposure-response relationships were proceeding when the entire data set was lost owing to the computer facility being struck by lightning. The proposed study seeks funds to recode the original raw data and to perform further analyses. In particular, the relationships of symptoms to sulfur dioxide exposure will be studied using maximum likelihood estimates obtained from a logistic model. Further analysis of the lung function tests will be performed, using adjusted and unadjusted parameters, to explore the effects, or lack thereof, of smoking and sulfur dioxide exposure. In particular, more sensitive indices of airflow obstruction (MMEF, flows at 75%, 50%, and 25% of FVC) than the FEV1, will be derived from the original spirographs and subjected to multiple regression analysis. The findings will provide important information on the effects of sulfur dioxide at steady, low concentrations and in the presence of very low levels of other air contaminants.